Inspection device, image forming apparatus, and program for inspection device

ABSTRACT

An image inspection device includes a hardware processor executing an inspection for a first read image generated by reading a first sheet on which one image is formed, based on a reference image. When an operation for newly generating the reference image is performed in association with the inspection for the first read image, the hardware processor acquires second read images generated by respectively reading second sheets on each of which the one image is formed and generates the reference image using the inspection for the first read image. When an operation for using the generated reference image stored in a storage unit is performed in association with the inspection for the first read image, the hardware processor uses the reference image in the storage unit for the inspection for the first read image, without newly acquiring the second read images.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of Ser. No.17/481,428, filed Sep. 22, 2021, the entire contents of which areincorporated herein by reference. Application 17,481,428 is acontinuation application of U.S. patent application Ser. No. 16/583,435,filed on Sep. 26, 2019 (U.S. Pat. No. 11,158,043), the entire contentsof which are incorporated herein by reference. The U.S. application Ser.No. 16/583,435 claimed the benefit of the date of the earlier JapanesePatent Application No. 2018-184381, filed on Sep. 28, 2018, priority towhich is also claimed herein, and the contents of which are alsoincorporated by reference.

BACKGROUND Technological Field

The present invention relates to an inspection device, an image formingapparatus, and a program for the inspection device.

Description of the Related Art

In a conventional example, after an image is formed on a paper sheet byan image forming apparatus, a scan image generated by reading the formedimage is compared with a reference image that is a normal image servingas a reference in an inspection. In this manner, printed matter havingan abnormality such as stains, creases, wrinkles, or skewing is detectedas waste paper.

Regarding such a technology, JP2011-112430A discloses the followingtechnology. An inspection image obtained by imaging a predeterminedportion of printed matter in which the same pattern is repeatedlyprinted is compared with a reference image stored in advance, so thatthe inspection image is evaluated. In a case where the inspection imageis determined to be defective, the inspection image is associated withthe reference image and is recorded together with the reference image,and the inspection image and the reference image are displayed. In acase where a determination indicating that the portion determined to bedefective is not a true defect is received by the user who has checkedthe displayed inspection image and the displayed reference image, thestored inspection image and the stored reference image are deleted.

However, in a case where an automatic inspection function thatassociates a print job for outputting printed matter of an inspectiontarget with a reference image, and detects waste paper by comparing ascan image of an image formed on a paper sheet on the basis of the printjob with the reference image is used, a plurality of reference imagesthat has been generated and stored in advance is normally used whenprinting is performed in print settings being changed. Therefore, alarge number of print jobs shares the automatic inspection function, anda large number of reference images is created. This takes up thecapacity of a storage device. As a result, a newly generated referenceimage might not be stored, and the automatic inspection function becomesunusable. Also, to avoid overuse of the capacity of the storage device,the user needs to manually select and delete a reference image which ishighly unlikely to be used in the future. By the above conventionaltechnology, such a problem is not solved, because it is not possible todelete a reference images stored in advance.

SUMMARY

The present invention has been made to solve such problems.Specifically, the present invention aims to provide an inspectiondevice, an image forming apparatus, and a program for the inspectiondevice that are capable of preventing a decrease in productivity,without forcing the user to manually delete unnecessary reference imagesto avoid shortage of capacity in the storage due to the reference imagesgenerated and stored when an automatic inspection function is executed.

To achieve the abovementioned object, according to an aspect of thepresent invention, an inspection device reflecting one aspect of thepresent invention comprises an image reader that generates a scan imageby reading an image formed on a recording medium by an image former on abasis of a print job, an inspector that inspects an inspection targetimage formed on a storage medium, by comparing a scan image with areference image, the scan image being generated by reading with theimage reader the inspection target image formed on a recording medium bythe image former on a basis of a first print job, the reference imagebeing a reference in an inspection of the inspection target image, astorage that stores the reference image, and a hardware processor thatstores into the storage the reference image generated as the scan imageby reading with the image reader an image formed on a recording mediumby the image former on a basis of a second print job for generating thereference image, determines whether the reference image stored in thestorage satisfies a predetermined condition when a data amount of thereference image stored in the storage becomes equal to or larger than apredetermined amount, and deletes the reference image determined tosatisfy the predetermined condition from the storage.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features provided by one or more embodiments of theinvention will become more fully understood from the detaileddescription given hereinbelow and the appended drawings which are givenby way of illustration only, and thus are not intended as a definitionof the limits of the present invention:

FIG. 1 is a schematic diagram showing the configuration of an imageforming system.

FIG. 2 is a block diagram showing the configuration of the image formingsystem.

FIG. 3 is a schematic view of an automatic inspection setting screen fordetermining whether to save a reference image after execution of aninspection job.

FIG. 4 is a flowchart showing an operation of the image forming system.

FIG. 5 is a flowchart showing an operation of the image forming system.

FIG. 6 is a flowchart showing an operation of the image forming system.

FIG. 7 is a flowchart showing an operation of the image forming system.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, one or more embodiments of the present invention will bedescribed with reference to the drawings. However, the scope of theinvention is not limited to the disclosed embodiments. In thedescription below with reference to the drawings, like components aredenoted by like reference numerals, and explanation of those componentswill not be repeated twice or more. The dimensional ratios in thedrawings are increased for ease of explanation and may differ from theactual dimensional ratios.

(Image Forming System)

FIG. 1 is a schematic diagram showing the configuration of an imageforming system according to an embodiment of the present invention. FIG.2 is a block diagram showing the configuration of an image formingsystem.

An image forming system 100 includes an image forming apparatus 101, areading apparatus 102, a post-processing apparatus 103, and a sheetfeeding apparatus 104. The image forming apparatus 101 performs imageformation (printing) on a recording medium (a paper sheet, for example).In the description below, a paper sheet S is as an example of therecording medium. The reading apparatus 102 reads an image formed on apaper sheet S. The post-processing apparatus 103 performspost-processing on a paper sheet having an image formed thereon. Thesheet feeding apparatus 104 supplies stored paper sheets S to an imageformer 30, in cooperation with a sheet feeder tray 41. Each of theseapparatuses may include some other apparatus. For example, the imageforming apparatus 101 may include the reading apparatus 102. The imageforming system 100 may be a production printer.

As shown in FIG. 2 , the image forming system 100 includes a controller10, a storage 20, the image former 30, a sheet feeding/conveying unit40, an operation display 50, a reader 60, a post-processing unit 70, anda communication unit 80. These components are mutually connected via abus for exchanging signals between the components. The reader 60 formsan image reader.

The controller 10 is a CPU and performs control on each component andvarious kinds of arithmetic processing in accordance with a program. Thecontroller 10 includes a controller 12 included in the image formingapparatus 101 and a controller 11 included in the reading apparatus 102,and these controllers cooperate to control the entire image formingsystem 100. The controller 10 and the reader 60 constitute an inspector.The control to be performed by the controller 10 will be described laterin detail.

The storage 20 includes a storage 22 included in the image formingapparatus 101 and a storage 21 included in the reading apparatus 102.The storage 20 includes a ROM that stores various programs and variouskinds of data, a RAM that serves as a work area to temporarily storeprograms and data, and a hard disk or the like that stores variousprograms and various kinds of data.

The image former 30 includes an intermediate transfer belt 31,photosensitive drums 32, developing units 33, writing units 34, and asecondary transfer unit 35.

The photosensitive drums 32, the developing units 33, and the writingunits 34 each have configurations corresponding to the respective basiccolors: yellow (Y), magenta (M), cyan (C), and black (K). In FIG. 1 ,reference numerals other than 32(Y) and 33(Y) are not shown for thephotosensitive drums 32 and the developing units 33.

The writing units 34 of the image former 30 exposes the surfaces ofelectrically charged photosensitive drums 32 and form electrostaticlatent images, on the basis of image data. In the developing units 33,the formed electrostatic latent images are developed with toners of thedeveloping units 33, and toner images in the respective colors areformed on the surfaces of the respective photosensitive drums 32. Thesetoner images are sequentially stacked on the intermediate transfer belt31 by primary transfer units (not shown) of the respective colors, sothat a full-color toner image is formed. This toner image is transferredonto a paper sheet S by the secondary transfer unit 35. After that, thepaper sheet S having the toner image formed thereon is conveyed to afixing unit 36, and the fixing unit 36 heats and presses the paper sheetS, to fix the full-color image to the paper sheet S.

The sheet feeding/conveying unit 40 includes the sheet feeder tray 41,conveyance paths 42 (42 a through 42 d), a plurality of conveyancerollers, a drive motor (not shown) for driving the conveyance rollers,and the sheet feeding apparatus 104.

The sheet feeding/conveying unit 40 rotates each conveyance roller atpredetermined timing by driving of the drive motor, to convey a papersheet S supplied from the sheet feeder tray 41 or the sheet feedingapparatus 104 to the image former 30.

In this example, the sheet feeder tray 41 is a two-stage pull-out trayformed with an upper tray 41 a and a lower tray 41 b each storing papersheets individually, and supplies paper sheets to the image formingapparatus 101.

The sheet feeding apparatus 104 stores more paper sheets than the uppertray 41 a and the lower tray 41 b inside the image forming apparatus101, and supplies paper sheets S to the image forming apparatus 101.

The conveyance paths 42 include conveyance paths 42 a and 42 d in theimage former 30, a conveyance path 42 b in the reading apparatus 102,and a conveyance path 42 c in the post-processing unit 70.

A paper sheet S supplied from the sheet feeding apparatus 104 or thesheet feeder tray 41 is conveyed in the conveyance path 42 a.Registration rollers 431 that adjust the timing to convey a paper sheetby rotating and stopping with a clutch is disposed in the conveyancepath 42 a.

A paper sheet S that has been conveyed in the conveyance path 42 a andhas an image formed thereon by the image former 30 passes through theconveyance paths 42 a and 43 c on the downstream side, is subjected torespective kinds of processing depending on the print settings for theprint job. After that, the paper sheet S is ejected out of the machine,and is placed onto a sheet catch tray 44. The print settings include “Nin 1” (page assignment), setting of the number of copies to be made,stapling, punching, folding, watermarking, document orientation, sheetsize, and grayscale setting, for example.

When the print settings for the print job are settings for double-sidedprinting, a paper sheet S having an image formed on one side (a firstside, usually the front side) thereof is conveyed to the ADU conveyancepath 42 d located below the image former 30. The paper sheet S conveyedto the ADU conveyance path 42 d is turned over in a switchback path.After that, the paper sheet S enters the conveyance path 42 a, and animage is formed on the other surface (a second surface, normally theback surface) of the paper sheet S in the image former 30.

The operation display 50 includes a touch-panel display, a numerickeypad, a start button, and a stop button. The operation display 50displays an input screen for inputting various instructions, a state ofthe apparatus, or the like, and receives various kinds of settings suchas print settings, and various kinds of instructions. The operationdisplay 50 functions as a receiver and a display.

The reader 60 generates a scan image in the conveyance path 42 b byreading an image formed on a paper sheet S that is passing in theconveyance path 42 b. The scan image may be data in a bitmap format, forexample. The reader 60 functions as an image reader.

The reader 60 includes a line image sensor, a lens optical system, alight emitting diode (LED) light source, and a housing that houses thesecomponents, and reads an image formed on a paper sheet S being conveyed.In the image reading, light from the LED light source illuminates thesurface of the paper sheet S passing through the reading position in theconveyance path 42 b, and an image of the reading position is guided bythe lens optical system, so that an image is formed on the line imagesensor.

The post-processing unit 70 is disposed in the conveyance path 42 c. Thepost-processing unit 70 performs a binding process, for example. Thepost-processing unit 70 includes a stacking unit that stacks papersheets, and a stapling unit. After the stacking unit stacks a pluralityof paper sheets S, the stapling unit performs a side stitching processusing staples. The bundle of paper sheets S subjected to side stitchingis ejected onto the sheet catch tray 44. Meanwhile, each paper sheet Snot subjected to side stitching is ejected as it is through theconveyance path 42 c.

The communication unit 80 may be any of the following various localconnection interfaces: network interfaces compliant with standards suchas SATA, PCI Express, USB, Ethernet (registered trademark), and IEEE1394, and wireless communication interfaces such as Bluetooth(registered trademark) and IEEE 802.11. Through the communication unit80, a print job including print data and print settings is received froman external terminal such as a PC.

On the basis of a print job, the controller 10 forms an image on a papersheet S with the image former 30 and generates a scan image by readingthe image formed on the paper sheet S with the reader 60. The controller10 inspects the image formed on the paper sheet S by comparing thegenerated scan image with a reference image (a correct image) associated(linked) with the print job. Hereinafter, an inspection of an imageformed on a paper sheet S will be simply referred to as “inspection”.The reference image serves as a criterion for inspection, being a normalimage. With this, an automatic inspection function is executed. In acase where the controller 10 determines, as a result of the inspection,that the image formed on the paper sheet S is abnormal, the controller10 determines that the paper sheet S on which the image determined to beabnormal is formed is waste paper, and is ejected onto a waste sheetcatch tray (not shown) that is prepared separately from the sheet catchtray 44. The abnormality in the image formed on the paper sheet Sdetermined to be waste paper may include a stain, a corner bend,wrinkles, and skew. Hereinafter, a print job for forming an image to beinspected on a paper sheet S will be referred to as an inspection job.Further, an image to be inspected will be referred to as an inspectiontarget image. As this inspection job is executed, a paper sheet Sdetermined to be non-defective as a result of inspection is output asprinted matter of a product. The inspection job forms a first print job.

On the basis of a print job for generating a reference image, thecontroller 10 forms an image on a paper sheet S with the image former 30and generates a scan image to be used as the reference image by readingthe image formed on the paper sheet S with the reader 60. After beingdetermined to be normal through a visual inspection or the likeconducted by the user, the generated scan image is associated as thereference image with an inspection job that is to use the referenceimage in the inspection and is stored into the storage 20. Hereinafter,the print job for generating the reference image will be referred to asthe reference image generation job. The reference image generation jobforms a second print job.

The reference image generation job may be a print job generated bychanging the number of copies in an inspection job from two or larger toone, for example. Further, in the reference image generation job, printsettings may be changed as necessary for each inspection job. When thereference image generation job is generated, the output mode may be asample output mode or a proof output mode, for example. The sampleoutput mode may be a mode in which one copy of printed matter is printedfor any of the stored inspection jobs, and a scanned image of theprinted matter is associated as the reference image with the inspectionjob and is stored together with the inspection job. The proof outputmode may be a mode in which, when one copy of printed matter is printedand is determined to be normal through a visual inspection before aninspection job is executed, a scan image of the printed matter is storedas the reference image, is associated with the inspection job, theinspection is conducted, and the inspection job is then deleted from thestorage 20 (or is not stored into the storage 20). In the descriptionbelow, for ease of explanation, the reference image generation job isexecuted in the sample output mode unless otherwise specified

When generating a reference image, the controller 10 performs control asfollows. The controller 10 associates a reference image generated byexecuting the reference image generation job with an inspection job andstores the reference image into the storage 20. The reference image maybe stored in the storage 21 of the reading apparatus 102, and the printjob may be stored in the storage 22 of the image forming apparatus 101.When the data amount of the reference images stored in the storage 21becomes equal to or larger than a predetermined amount, the controller10 determines whether the stored reference images satisfy apredetermined condition. A reference image determined to satisfy thepredetermined condition is then deleted from the storage 21. The amountof data serving as the criterion for determination of deletion of areference image may be set at 90% to 100% of the storage capacity of thestorage 21, for example. The predetermined condition includes thefollowing conditions, for example.

(1) A reference image that has a frequency of usage for inspection equalto or lower than a predetermined frequency (a first condition). Thepredetermined frequency may be set at an appropriate value determinedthrough an experiment or the like. For example, the predeterminedfrequency may be set as three to five times a month.

(2) A reference image that was stored into the storage 21 before apredetermined time and date, was last edited before the predeterminedtime and date, and/or was last used for inspection before thepredetermined time and date (a second condition). The time and date whena reference image was stored into the storage 21, the time and date whenthe reference image was edited last time, and the time and date when thereference image was used for inspection last time may be stored as timestamps in the header of the file of the reference image. Thepredetermined time and date may be set at appropriate values determinedthrough an experiment or the like. For example, the predetermined timeand date may be set between a date and time one month ago and a date andtime one year ago.

(3) A reference image not associated with an inspection job in aplurality of reference images that is to be used for inspection in theinspection job in the sample output mode and is stored in the storage 21(a third condition).

(4) A reference image that is to be used for inspection of an inspectiontarget image formed by executing an inspection job having aconfidentiality level equal to or higher than a predetermined level (afourth condition). The predetermined level may be set as appropriate inview of the security policy or the like of each organization. The job IDof an inspection job that uses the reference image for inspection may bestored in the header of the file of the reference image.

(5) A reference image that has been used in an executed inspection jobin a setting in which a reference image used for inspection afterexecution of an inspection job is to be deleted (a fifth condition). Thesetting may be set in accordance with a user instruction that is inputfrom the operation display 50.

(6) A reference image that meets at least one of the following setcriteria: the expiration date of the reference image, the number ofinspection jobs that have used the reference image in inspectinginspection target images, and the number of paper sheets on whichinspection target images have been inspected with the use of thereference image (a sixth condition). The expiration date of thereference image, the number of inspection jobs that have used thereference image in inspecting inspection target images, and the numberof paper sheets on which inspection target images have been inspectedwith the use of the reference image may be set in accordance with a userinstruction that is input from the operation display 50.

(7) A reference image that corresponds to the other reference image in asetting in which another reference image having the same file name as areference image being stored is already stored in the storage 21 and isto be overwritten by the reference image being stored (a seventhcondition). The setting may be set in accordance with a user instructionthat is input from the operation display 50.

(8) A reference image for which a deleting option has been receivedamong a plurality of reference images displayed on the operation display50 (an eighth condition). The deleting option may be received whenreference images are displayed in the form of thumbnails or the like ina selectable manner on the operation display 50, for example.

(9) A reference image generated through execution of a reference imagegeneration job in different print settings from the print settings of aninspection job in a case where a plurality of reference images to beused in inspecting inspection target images formed through execution ofan inspection job are generated and stored by executing a plurality ofreference image generation jobs having different print settings (a ninthcondition).

(10) A reference image associated with an inspection job in a case whereupdating has been performed to change the print settings of theinspection job stored in the storage 21 or the storage 22 (a tenthcondition). The changes in the print settings include a change in thepage sequence, and a change in the position or the range of an image,for example.

The predetermined condition may be any one condition, or an AND or an ORof two or more conditions selected from the first through tenthconditions by the user.

FIG. 3 is a schematic view of an automatic inspection setting screen fordetermining whether to save a reference image after execution of aninspection job.

An automatic inspection setting screen 503 is displayed by selecting“automatic inspection” 502 from among the items in “output settings” 501on a job ticket editing screen 500. The items other than the “automaticinspection” 502 among the items in the “output settings” 501 are thesame as those in an image forming system having a conventional automaticinspection function, and therefore, are not described in detail herein.

The automatic inspection setting screen 503 includes “inspectionsettings” 504 for setting ON/OFF of the automatic inspection function,“reference image settings” 505 for determining whether to newly create areference image or whether to select a reference image from amongregistered images, and “inspection level settings” 506 for setting aninspection level. In the example shown in FIG. 3 , “ON” is selected inthe “inspection settings” 504. “Newly Create” is selected, and “Deleteat End” is selected in the “reference image settings” 505. “High” isselected in the “inspection level settings” 506. The inspection levelsare the same as those in an image forming system having a conventionalautomatic inspection function, and therefore, is not described herein.

When the above selection is made, and an “OK” button is selected, “NewlyCreate” is selected, and settings are made so that a reference image tobe used for inspection using the automatic inspection function is newlycreated. Further, as “Delete at End” is selected, settings are made sothat the created reference image will be deleted from the storage 21after execution of the inspection job. In this case, the fifth conditiondescribed above is set as the predetermined condition.

Operation of the image forming system is now described.

FIG. 4 is a flowchart showing an operation of the image forming systemin a case where the first condition and the second condition are set asthe predetermined condition for deleting a reference image. Thisflowchart may be executed by the controller 11 of the reading apparatus102 in accordance with a program stored in the storage 21. Note thatpart of this flowchart may be executed by the controller 11 and thecontroller 12 cooperating with each other. Likewise, the flowchartsshown in FIG. 5 through FIG. 7 described later may also be executed bythe controller 11 (or partially in cooperation with the controller 12)in accordance with a program.

The controller 11 determines whether the usage rate of the storage 21 isequal to or higher than a predetermined value (S101). The predeterminedvalue may be 100%, for example. The usage rate of the storage 21corresponds to the data amount of the reference images stored in thestorage 21, and the usage rate and the data amount are convertible toeach other. If the controller 11 determines that the usage rate of thestorage 21 is not higher than the predetermined value (S101: NO), thecontroller 11 ends the process.

If the controller 11 determines that the usage rate of the storage 21 ishigher than the predetermined value (S101: YES), the controller 11determines whether a setting for deleting reference images in ascendingorder of usage frequency has been made (S102). The setting for deletingreference images in ascending order of usage frequency may be a settingfor deleting the reference image(s) having a usage frequency equal to orlower than a predetermined value (three times a month, for example). Ifthe controller 11 determines that the setting for deleting referenceimages in ascending order of usage frequency has been made (S102: YES),the controller 11 determines whether a setting for deleting referenceimages in chronological order in terms of update time and date has beenmade. (S103). The setting for deleting reference images in chronologicalorder in terms of update time and date may be a setting for deleting thereference images that were last updated before a predetermined time anddate (at least one month ago, for example). If the controller 11determines that the setting for deleting reference images inchronological order in terms of update time and date has been made(S103: YES), the controller 11 deletes the reference image(s) having ausage frequency equal to or lower than the predetermined value, andfurther deletes the reference image(s) that was (were) last updatedbefore the predetermined time and date (S104).

If the controller 11 determines that the setting for deleting referenceimages in chronological order in terms of update time and date has notbeen made (S103: NO), the controller 11 deletes the reference image(s)having a usage frequency equal to or lower than the predetermined value(S105).

If the controller 11 determines in step S102 that the setting fordeleting reference images in ascending order of usage frequency has notbeen made (S102: NO), the controller 11 determines whether a setting fordeleting reference images in chronological order in terms of update timeand date has been made. (S106). If the controller 11 determines that thesetting for deleting reference images in chronological order in terms ofupdate time and date has not been made (S106: NO), the controller 11ends the process.

If the controller 11 determines that the setting for deleting referenceimages in chronological order in terms of update time and date has beenmade (S106: YES), the controller 11 deletes the reference image(s) thatwere (was) last updated before the predetermined time and date (S107).

FIG. 5 is a flowchart showing an operation of the image forming systemin a case where the third condition is set as the predeterminedcondition for deleting a reference image.

The controller 11 determines whether a reference image generation jobhas been executed in the sample output mode (S201). If the controller 11determines that the reference image generation job has not been executedin the sample output mode (S201: NO), the controller 11 ends theprocess.

If the controller 11 determines that the reference image generation jobhas been executed in the sample output mode (S201: YES), the controller11 stores the generated reference image into the storage 21 (S202), andthen determines whether the reference image generation job has beenre-executed in the sample output mode (S203). If the controller 11determines that the reference image generation job has been re-executedin the sample output mode (S203: YES), the controller 11 stores thegenerated reference image into the storage 21 (S202), and thendetermines whether the reference image generation job has beenre-executed in the sample output mode (S203). The controller 11 repeatssteps S202 and S203.

If the controller 11 determines that the reference image generation jobhas not been re-executed in the sample output mode (S203: NO), thecontroller 11 selects a reference image to be used for inspection in aninspection job (S204), and executes the inspection job (S205).

The controller 11 determines whether the storage 21 stores referenceimages that have not been used for inspection in the inspection job(S206). That is, in a case where a plurality of reference images to beused in inspection jobs has been generated in the sample output mode,the controller 11 determines whether the storage 21 stores referenceimages not associated with the executed inspection job. If thecontroller 11 determines that any reference image not used forinspection in the inspection job is not stored in the storage 21 (S206:NO), the controller 11 ends the process.

If the controller 11 determines that the storage 21 stores one or morereference images not used for inspection in the inspection job (S206:YES), the controller 11 deletes the unused reference image(s) from thestorage 21 (S207).

FIG. 6 is a flowchart showing an operation of the image forming systemin a case where the fourth condition and the fifth condition are set asthe predetermined condition for deleting a reference image.

The controller 11 executes an inspection job until the output iscompleted (S301 and S302).

If the controller 11 determines that the output of the inspection jobhas been completed (S302: YES), the controller 11 determines whether asetting for deleting an inspection image at the end of an inspection jobhas been made (S303). If the controller 11 determines that the settingfor deleting an inspection image at the end of an inspection job hasbeen made (S303: YES), the controller 11 deletes the reference imageused for inspection in the inspection job from the storage 21 (S304).

If the controller 11 determines that the setting for deleting aninspection image at the end of an inspection job has not been made(S303: NO), the controller 11 determines whether the executed inspectionjob is a confidential job (S305). That is, the controller 11 determineswhether the confidentiality level of the inspection job is set to apredetermined level or higher. If the controller 11 determines theexecuted inspection job not to be a confidential job (S305: NO), thecontroller 11 ends the process.

If the controller 11 determines the executed inspection job to be aconfidential job (S305: YES), the controller 11 deletes the referenceimage used for inspection in the inspection job from the storage 21(S304).

FIG. 7 is a flowchart showing an operation of the image forming systemin a case where the seventh condition is set as the predeterminedcondition for deleting a reference image.

The controller 11 starts storing a reference image into the storage 21(S401) and determines whether the storage 21 stores a reference imagehaving the same file name as the file name of the reference image to bestored (S402). If the controller 11 determines that the storage 21 doesnot store any reference image having the same file name as the file nameof the reference image to be stored (S402: NO), the controller 11 storesthe new reference image into the storage 21 (S405).

If the controller 11 determines that the storage 21 stores a referenceimage having the same file name as the file name of the reference imageto be stored is stored (S402: YES), the controller 11 determines whethera setting for storing a reference image in an overwriting manner hasbeen made (S403). The controller 11 determines that the setting forstoring a reference image in an overwriting manner has been made (S403:YES), the controller 11 deletes the reference image having the same filename already stored in the storage 21 (S404) and stores the newreference image into the storage 21 (S405).

If the controller 11 determines that the setting for storing a referenceimage in an overwriting manner has not been made (S403: NO), thecontroller 11 changes the file name of the new reference image (S406)and stores the new reference image into the storage 21.

This embodiment has the effects described below.

In a case where the data amount of the reference images generated andstored when an automatic inspection function was executed is equal to orlarger than a predetermined amount, each reference image satisfying apredetermined condition is deleted. As a result, it is possible toprevent a decrease in productivity, without forcing the user to manuallydelete unnecessary reference images to avoid shortage of capacity in thestorage due to the reference images generated and stored when anautomatic inspection function is executed.

Further, from among the reference images stored in the storage, areference image to be used for inspection of an inspection target imageis selected by the user, and the inspection target image is inspectedwith the use of the selected reference image. Because of this, it ispossible to conduct an inspection using an appropriate reference image,and improve waste paper detection accuracy accordingly.

Furthermore, the usage frequency of each reference image is stored, andthe predetermined condition for deleting a reference image is the firstcondition that the usage frequency of a reference image stored in thestorage is equal to or lower than a predetermined frequency. Because ofthis, it is possible to appropriately delete a reference image with alow degree of necessity.

Further, the date and time of storage, the date and time of the mostrecent editing, and the date and time of the most recent usage forinspection are stored for each reference image, and the predeterminedcondition for deleting a reference image is the second condition thatthe date and time of storage, the date and time of the most recentediting, and/or the date and time of the most recent usage forinspection is earlier than a predetermined time and date. Because ofthis, it is possible to appropriately delete a reference image with alow degree of necessity.

Furthermore, in a case where a plurality of reference images to be usedfor inspection in an inspection job are generated and stored into thestorage in the sample output mode, one of the generated reference imagesis associated with the first print job, and the predetermined conditionfor deleting a reference image is the third condition that the referenceimage is not associated with the inspection target job. Because of this,it is possible to conduct an inspection using an appropriate referenceimage, and improve waste paper detection accuracy accordingly.

Further, a confidentiality level setting instruction is received for aninspection job, and the predetermined condition for deleting a referenceimage is the fourth condition that the reference image is to be used forinspection of an inspection target image formed through execution of aninspection job set at a confidentiality level equal to or higher than apredetermined level. Because of this, it is possible to prevent leakageof confidential information having a high confidentiality level bydeleting a reference image including information that should be treatedas confidential information such as personal information.

Furthermore, an instruction to delete the reference image used forinspection of an inspection target image formed on the basis of aninspection job after the inspection job is executed is received from theuser, and the predetermined condition for deleting a reference image isthe fifth condition that the reference image has been used forinspection in the executed inspection job. Because of this, it ispossible to appropriately delete the unnecessary reference image usedfor inspection in an inspection job that does not involve reprinting.

Further, an instruction to set an expiration date of a reference image,the number of inspection jobs for inspecting inspection target imagesusing a reference image, and/or the number of paper sheets on whichinspection target images are inspected with the use of a reference imageis received from the user and is set, and the predetermined conditionfor deleting a reference image is the sixth condition that the referenceimage has reached the set reference image expiration date, the setnumber of inspection jobs, and/or the set number of paper sheets.Because of this, it is possible to appropriately delete a referenceimage with a low degree of necessity.

Furthermore, in a case where another reference image having the samefile name as the reference image to be stored into the storage isalready stored in the storage, an instruction to store a reference imagein an overwriting manner is received from the user and is set, and thepredetermined condition for deleting a reference image is the seventhcondition that the reference image corresponds to the other referenceimage in a case where the setting for storing a reference image in anoverwriting manner and a reference image having the same file name asthat of the reference image is already stored in the storage when thereference image is to be stored into the storage. Because of this, it ispossible to leave a necessary reference image, and delete an unnecessaryreference image, in accordance with the user's intention.

Further, the reference images stored in the storage are displayed, thereference image to be deleted from among the displayed reference imagesis received by the user, and the predetermined condition for deleting areference image is the eighth condition that the reference image is theselected reference image. Because of this, it is possible to delete aless necessary reference image at appropriate timing.

Furthermore, the predetermined condition for deleting a reference imageis the ninth condition that the reference image is a reference imagegenerated through execution of a reference image generation job indifferent print settings from the print settings of an inspection job,in a case where a plurality of reference images to be used in inspectinginspection target images formed through execution of an inspection jobare generated and stored by executing a plurality of reference imagegeneration jobs having different print settings. Because of this, it ispossible to appropriately delete a reference image that has becomeunnecessary due to a print setting error or the like.

Further, an inspection job is associated with a reference image and isstored into the storage or into a storage device other than the storage,and the predetermined condition for deleting a reference image is thetenth condition that the reference image is a reference image associatedwith a stored inspection job in a case where the print settings for thestored inspection job have been updated. Because of this, it is possibleto appropriately delete a reference image that has become unnecessarydue to a print setting error or the like.

The configurations of the image forming system, the image formingapparatus, and the program described above are principal configurationsfor describing the features of the above embodiment. Embodiments of thepresent invention are not limited to the above embodiment, and variousmodifications may be made to it within the scope of the claimedinvention. Further, the configurations of general image forming systemsand the like are not excluded.

The means and the methods for performing various processes in the imageforming system according to the above-described embodiment can also beobtained through a special-purpose hardware circuit or a programmedcomputer. The program described above may be provided via acomputer-readable recording medium such as a USB memory or a DVD(Digital Versatile Disc)-ROM or may be delivered online via a networksuch as the Internet. In this case, the programs recorded in acomputer-readable recording medium are normally transferred to andstored into a storage such as a hard disk. Alternatively, the programdescribed above may be provided as independent application software ormay be incorporated as a function into the software of a device such asa detector.

Although embodiments of the present invention have been described andillustrated in detail, the disclosed embodiments are made for purposesof illustration and example only and not limitation. The scope of thepresent invention should be interpreted by terms of the appended claims.

What is claimed is:
 1. An image inspection device, comprising: ahardware processor which executes an inspection for a first read imagegenerated by reading a first sheet on which one image is formed, basedon a reference image, wherein in the case where an operation for newlygenerating the reference image is performed in association with theinspection for the first read image, the hardware processor acquires aplurality of second read images generated by respectively reading aplurality of second sheets on each of which the one image is formed, andgenerates the reference image using the inspection for the first readimage, the hardware processor stores the generated reference image in astorage unit, and in the case where an operation for using the referenceimage stored in the storage unit is performed in association with theinspection for the first read image, the hardware processor uses thereference image stored in the storage unit for the inspection for thefirst read image, without newly acquiring the second read images.
 2. Theimage inspection device according to claim 1, wherein the hardwareprocessor further receives a setting of an inspection level of theinspection for the first read image.
 3. The image inspection deviceaccording to claim 1, wherein the hardware processor performs adetermination of whether or not there is stain in the first read image,based on the reference image, as the inspection for the first readimage.
 4. The non-transitory recording medium storing a computerreadable program causing a computer of an image inspection device whichexecutes an inspection for a first read image generated by reading afirst sheet on which one image is formed, based on a reference image,and performs: in the case where an operation for newly generating thereference image is performed in association with the inspection for thefirst read image, acquiring a plurality of second read images generatedby respectively reading a plurality of second sheets on each of whichthe one image is formed, and generating the reference image using theinspection for the first read image; and storing the generated referenceimage in a storage unit, wherein the image inspection device, in thecase where an operation for using the reference image stored in thestorage unit is performed in association with the inspection for thefirst read image, uses the reference image stored in the storage unitfor the inspection for the first read image, without newly acquiring thesecond read images.
 5. The non-transitory recording medium storing acomputer readable program according to claim 4, wherein the programfurther causes the computer to receive a setting of an inspection levelof the inspection for the first read image.
 6. The non-transitoryrecording medium storing a computer readable program according to claim4, wherein the program causes the computer to perform a determination ofwhether or not there is stain in the first read image, based on thereference image, as the inspection for the first read image.
 7. An imageinspection system, comprising: an image formation unit which forms animage on a sheet; an image reading unit which generates a read image byreading a sheet on which an image is formed by the image formation unit;and a hardware processor which executes an inspection for a first readimage generated by reading, by the image reading unit, a first sheet onwhich one image is formed by the image formation unit, based on areference image, wherein in the case where an operation for newlygenerating the reference image is performed in association with theinspection for the first read image, the hardware processor acquires aplurality of second read images generated by respectively reading aplurality of second sheets on each of which the one image is formed, andgenerates the reference image using the inspection for the first readimage, the hardware processor stores the generated reference image in astorage unit, and in the case where an operation for using the referenceimage stored in the storage unit is performed in association with theinspection for the first read image, the hardware processor uses thereference image stored in the storage unit for the inspection for thefirst read image, without newly acquiring the second read images.
 8. Theimage inspection system according to claim 7, wherein the hardwareprocessor further receives a setting of an inspection level of theinspection for the first read image.
 9. The image inspection systemaccording to claim 7, wherein the hardware processor performs adetermination of whether or not there is stain in the first read image,based on the reference image, as the inspection for the first readimage.
 10. An image inspection method executed by an image inspectionsystem comprising: an image formation unit which forms an image on asheet; an image reading unit which generates a read image by reading asheet on which an image is formed by the image formation unit; and ahardware processor which executes an inspection for a first read imagegenerated by reading, by the image reading unit, a first sheet on whichone image is formed by the image formation unit, based on a referenceimage, the image inspection method comprising: in the case where anoperation for newly generating the reference image is performed inassociation with the inspection for the first read image, acquiring aplurality of second read images generated by respectively reading aplurality of second sheets on each of which the one image is formed, andgenerating the reference image using the inspection for the first readimage; and storing the generated reference image in a storage unit,wherein in the case where an operation for using the reference imagestored in the storage unit is performed in association with theinspection for the first read image, the hardware processor uses thereference image stored in the storage unit for the inspection for thefirst read image, without newly acquiring the second read images. 11.The image inspection method according to claim 10, further comprisingreceiving a setting of an inspection level of the inspection for thefirst read image.
 12. The image inspection method according to claim 10,wherein the hardware processor performs a determination of whether ornot there is stain in the first read image, based on the referenceimage, as the inspection for the first read image.